Objects

Lecture 146:- Objects

An object is a data structure in JavaScript that stores data in the form of key-value pairs. Each key in an object is a string or symbol that maps to a value. These values can be of any type, including strings, numbers, booleans, arrays, functions, and even other objects.

Objects are used extensively in JavaScript and are a key component of the language. They are used to represent real-world objects, like a person or a car, and can be used to group related data and functionality together.

To create an object, you can use object literal notation, which uses curly braces to define the object and its properties:

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const person = {  name: 'John',  age: 30,  hobbies: ['reading', 'swimming', 'hiking'],  address: {    street: '123 Main St',    city: 'Anytown',    state: 'CA',    zip: '12345'  },  sayHello: function() {    console.log(`Hello, my name is ${this.name}`);  } };

In this example, we define an object called person with several properties, including name, age, hobbies, address, and sayHello. The address property is itself an object, with its own properties.

You can access the properties of an object using dot notation or bracket notation:

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console.log(person.name); // output: John console.log(person['age']); // output: 30

You can also add new properties to an object or update existing ones:

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person.email = '[email protected]'; person.age = 31;

Objects can also be used as a way to pass data between functions, allowing you to group related data together and pass it as a single argument:

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function greetPerson(person) {  console.log(`Hello, ${person.name}!`); } greetPerson(person); // output: Hello, John!